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Archive | May 2016

Although their large trumpet-shaped blooms are a familiar display during the Christmas holiday season, Dutch hybrid amaryllises (Hippeastrum hybrids) are easy-to-grow bulbs that bloom naturally outdoors from mid-May to early June. Except for gardeners in the Mountains, these amaryllises will come back for the rest of us year-after-year.

SC Botanic Garden May 9, 2016

Growing amaryllises outdoors is fairly easy. Select a well-drained location in full or partial sun and plant the neck of the bulb where the leaves emerge about 2 to 4 inches below the soil surface. Follow-up with a 2 to 3 inch layer of mulch to conserve moisture and suppress weak growth. In subsequent years, apply a slow-release fertilizer in the spring, if necessary, when the new leaves emerge.

I grow the Dutch hybrids to impress my friends. I grow another amaryllis for me. St. Joseph’s lily (H. x johnsonii) was hybridized in the late 1700s by an English watchmaker named Arthur Johnson. The flowers are deep red with white stripes, and only a half-hand in diameter. They also have a spicy fragrance. Unlike the single-stem

Easley, SC May 7, 2016

med Dutch hybrids, St. Joseph’s lily can produce as many as four stems per bulb bearing 4 to 6 flowers on each stem.

St. Joseph’s lilies thrive with little care, which is part of their appeal. They enjoy our hot unforgiving summers and are indifferent about being watered during the growing season. Every year I’ve been rewarded with dazzling red flowers from these old-timey happy-go-lucky bulbs.

Like my Mom told me years ago, newer isn’t always better. How right she was. Mother’s are never wrong.

Last week I adopted some bearded irises from a friend’s garden. While it’s not the best time to move irises-when they’re in full bloom-it was necessary for a number of reasons: Gloria had to downsize her garden, she knew that bearded irises are my wife, Susan’s, favorite flower, and Mother’s Day was right around the corner.

As I lifted the irises out of the ground, I quickly discovered that Gloria knew the secret to gardening. The rich, black soil reminded of a radio interview I conducted with Roger Swain, the man with the red suspenders” and former host of The Victory Garden on PBS. I asked Roger, “What is the secret to gardening?” Quickly he replied: “It’s the soil, stupid.”

He’s right. Oftentimes we get caught up in the beauty and performance of ornamental and edible plants without remembering that the foundation for any healthy landscape, garden, or lawn is soil. A healthy soil allows air, water, and nutrients to be absorbed by plant’s roots and lets those roots roam freely.

How do you build healthy soil? Test the soil and add organic matter. A soil test measures the pH or acidity of the soil and the level of nutrients available for plant growth. Contact your local Clemson Extension Service office or acquire the soil sampling form online. Results from your soil test will indicate the amount of limestone or sulfur required to increase or lower the soil pH to an ideal range, which is between 5.8 and 6.5 for most vegetable and flower gardens, shrubs, trees, and lawns. If the pH is too low or too high, nutrients can get “tied-up” in the soil and not be absorbed by the roots. Also, maintaining an appropriate pH creates an environment that supports helpful soil-dwelling organisms, including earthworms.

The soil test results will also inform you of any minerals that may have to be added to improve the fertility levels of your soil. If your soil already has high levels of phosphorus and potassium, for example, there’s no need to purchase a fertilizer containing these two nutrients (the last two numbers on a fertilizer label). There’s already enough in the soil to meet the plant’s needs, assuming that the soil pH is in the desirable range.

Besides soil testing, holistic gardeners add organic matter. Organic matter improves soil tilth–its physical condition or structure. When added to clay soil, organic matter holds the clay soil particles apart and groups them into small pieces. This improved structure improves air and water movement in the soil, which translates to deeper and more extensive root development in our plants.

The kind of organic matter you mix into your soil is your choice. My grandfather liked to use rabbit and chicken manure for his vegetable and flower beds. My mother liked using fish in her rose garden. As a child I used to bundle fish heads, tails, and other inedible parts in newspaper and then bury them around her roses. If you’re squeamish about using these organic materials, then add compost or shredded leaves. Cover or “green manure” crops such as crimson clover or annual rye are relatively inexpensive sources of organic matter. Sow these crops in the fall and then turn them under in the spring to enrich the soil.

Some gardener forsake organic matter for gypsum or sand, believing that either of these amendments will “loosen” their heavy clay soil. Because our piedmont soils do not have an alkaline soil pH or high levels of sodium like the soils in the Southwest, don’t bother with gypsum. To improve soil structure, add organic matter and maintain the right soil pH by liming.

If you’ve ever attempted to “fix” clay soil with a few handfuls of sand, you’d be pretty surprised by the outcome. You may discover that your annual flower bed is better suited for making bricks instead of growing marigolds and petunias. Stick with organic matter.

I drove home with a two dozen irises in my trunk. As I glanced down at my blackened hands on the wheel, I knew that my wife will appreciate this Mother’s Day gift of passalong irises. But will the irises like my red clay?

This article, which appeared in Jan/Feb issue of The South Carolina Nurseryman (p. 4-5), was cowritten with Mary Ridgeway, Director of Kalmia Gardens of Coker College in Hartsville, SC. Since 1935 Kalmia Gardens has been open to the public free of charge from dawn until dusk, every day of the year.

In this issue we spotlight Camellia japonica ‘Lois Coker’, which was suggested by Mary Ridgeway, Director of Kalmia Gardens of Coker College in Hartsville. It wasn’t the text in her July 17, 2014 email that bowled me over, but the attached photograph. I was immediately smitten by this perfectly sculpted flower.

‘Lois Coker’ camellia. Credit: Ione Lee.

Since the early 1980s Lois Coker Japanese camellia has accentuated the woodland plantings at Kalmia Gardens, which are home to several hundreds of other camellias species and cultivars. I wanted to know: who is Lois Coker and where did this cultivar come from?

I learned the background story of the ‘Lois Coker’ Japanese camellia from an email written by Ione Coker Lee:

“My father, Robert R. Coker, President of Coker’s Pedigreed Seed Company, discovered the white curved petals of a seedling growing under a ‘Magnolia Flora’ camellia in their backyard. It is a creamy-white camellia and bears no resemblance to the pale pink ‘Magnolia Flora’. The petal structure is entirely different as well.

Nurseryman and owner of County Line Nursery in Byron, Georgia, grows ‘Lois Coker’ and includes the following description on his web site[2]: “This flower will cause one to do a double-take. It has a distinct yellow shadow that is hard to reproduce in a photo.”

‘Lois Coker’ on left, ‘Magnoliiflora’ on right. Credit: Ione Lee.

I spoke to Mr. Alden about ‘Lois Coker,’ and I sensed his fondness for this cultivar. Several times he mentioned the unique yellow sheen that’s reflected by the white petals. Alden said this midseason bloomer can be expected to mature to a height of 8 to 10 ft. It can be shaped easily with judicious pruning. Cuttings root similarly as other camellias and do not require any special treatment–only time and patience.

While ‘Lois Coker’ is still winning awards at American Camellia Society shows (5 during the 2012-2013 season[3]), it’s time that this southern born-and-raised cultivar, which was the result of a happenstance discovery, goes mainstream and finds a home in southern landscapes. Some of us need the head-turning, jaw-dropping, take-me-to-my-happy-place flowers of ‘Lois Coker’ to help us cope with the dreary short days of winter.

After its publication, I received this email from Ms. Lee:Sent: Friday, January 02, 2015 9:19 AM
Dear Bob: I had a call from Ryan Gainey this week telling me he had a copy of 1976 American Camelia Society bulletin in which the ‘Lois Coker’ was introduced. There is more information about its cultivation which would be of interest for your article. Apparently it took 10 years to grow from seed. Ryan Gainey is a prominent plantsman and native of Hartsville also (and a Clemson graduate). You might want to get in touch with him if you still have time before article is published. Happy New Year! Ione

This article was published in The South Carolina Nurseryman, March/April 2015, p. 38-39. It was co-written with Kathy Bridges, Landscape Manager and Student Coordinator, South Carolina Botanical Garden. Since its publication, I became aware that its scientific name has been changed to Cartrema americana.

With the common name of devilwood (Osmanthus americanus), you would expect this extremely hard-wooded species to be better suited for making Harry Potter wands[1] than adorning the landscape as an attractive evergreen shrub or small tree. However, it does have landscape merit, although few people know it. This Southeastern native joins other “underused” horticultural gems as it languishes in obscurity. It’s a favorite among native plant aficionados or horticulture instructors like Kathryn White at Piedmont Technical College in Greenwood: “The fact that it is native to the southeast and has good pest resistance would make it an excellent alternative to plants such as Leyland cypress or red

Closeup of Osmanthus americanus flowers. Credit: Kathy Bridges.

tips (Photinia xfraseri). Other wonderful characteristics of devilwood are fragrant flowers and fruit that’s attractive to wildlife. For the gardener wanting to add a native plant to their landscape or someone just looking to add a low fuss plant into their landscape this is one that should definitely be considered.”

Osmanthus americanus is a dioecious evergreen shrub or small multi-trunked tree that grows 15 to 25 feet tall and 10 to 15 feet wide. Panicles of creamy-white fragrant flowers appear in early spring that give rise to dark blue drupes in late summer. In the SC Botanic Garden devilwood thrives beneath the high shade of pines and in exposed dry locations (in full sun the leaves taken on more yellowish tones). Although native to the edges of swamps and streams in the coastal plain, this highly adaptable species exhibits excellent drought tolerance that lends itself to naturalized landscapes, rain gardens, and in backyard wildlife habitats where it acts as a magnet for birds and butterflies.

Osmanthus americanus cuttings prepared by Spartanburg Community College students as part of their Plant Propagation class. Credit: Kevin Parris.

Unfortunately, it’s not a common denizen of landscapes because “it has no single striking trait,” as suggested by Dr. Mellichamp[2], Director of the UNC Charlotte Botanical Gardens. (Sadly, it wasn’t included in Dick Bir’s book[3]). Devilwood also sports a variety of forms, according to Ted Stephens, co-owner of Nurseries Caroliniana, who said: “This is one species where there really needs to be some clonal selections. Our customers bought them mostly for screens because the form was not good enough for a foundation plant.”

Kevin Parris, Horticulture Instructor/Arboretum Director at Spartanburg Community College propagated a desirable clone at Gilbert’s Nursery in Chesnee in the mid-1990s. “The parent plant was located in the landscape of the Fred Blackley Landscape Architecture offices in Shelby, NC. It has more narrow foliage and shorter internodes than the typical species, giving it the form and texture of Myrica cerifera, for which it is an outstanding alternative in colder climates. Gilbert’s has propagated thousands of this clone over the years, so if you stumble onto a nursery produced Osmanthus americanus in a commercial or residential setting, there is a good chance it traces back to the parent plant in Shelby.”

Bob Head, plant breeder and co-owner of Head Ornamentals® and Head Select®, has been selecting O. americanus for years. In addition to a variegated form with double flowers, he’s been collecting forms with big wide leaves and full sun tolerance. Head recommends O. americanus in a lightly shaded site as a small accent tree with a single, dominant trunk, where it can be appreciated for its fragrant flowers, absence of pests, and beautiful, spine-free evergreen leaves.

Propagating O. americanus from seed can be a daunting task due to double dormancy

issues. However, Parris and the students in his Plant Propagation class have achieved success in rooting cuttings taken from late winter to early spring. They dip them in 2000 ppm K-IBA and 1000 ppm NAA and then root them under intermittent mist. They have also achieved good results with firm semihardwood cuttings in late summer to early fall.

Admittedly O. americanus lacks the does not have the star power as its Asian counterparts, such as O. heterophyllus ‘Goshiki’, O. xfortunei, or O. fragrans ‘Fudingzhou’. These species enjoy widespread consumer acceptance without the help of publicist or a Don King-like promoter. Hopefully the introduction of tighter, denser, forms–even dwarf selections, and maybe with a little magic, devilwood will become a highly sought-after contender one day.

Big can be beautiful. Growing 30 to 50 ft. high and 40-50 ft. wide, yellowwood (Cladrastis kentukea) sports smooth brown-gray bark (similar to American beech) and an upright, rounded and irregular crown. You’ll find this native growing wild on slopes and ridges, along stream banks, roadsides, and old fields. The common name yellowwood refers to the yellow dye that colors its heartwood.

Fragrant panicles of yellowwood flowers.

Although this American native was introduced into the nursery trade in 1812, yellowwood lacks the widespread appeal of the vertically challenged dogwoods. Nevertheless, yellowwood deserves a place in the landscape. I’m fond of its distinctive 8- to 12-inch long, compound pea-green leaves that turn butter yellow to golden orange in fall. However, I’m most impressed by its May floral display: six to twelve-inch long panicles of white fragrant flowers reminiscent of wisteria; they give rise to 3- to 5-inch long brown beanlike pods. This breathtaking floral display is always a special event because yellowwood has a boom-bust cycle of flowering: one year it produces copious numbers of flowers and in the second, sometimes third year, a lighter display. Although it doesn’t bloom reliably every year, its other features make the wait worthwhile.